getwd();
## [1] "E:/Users/Admin/Google Drive/MiApp/kinito.seminar.under"
#setwd("~/Desktop");
ls();
## character(0)
#rm(list=ls());
my_number <- 42;
print(my_number);
## [1] 42
chv1 <- "hello";
print(chv1);
## [1] "hello"
x <- 6+4;
print(x);
## [1] 10
y <- 4;
x / y;
## [1] 2.5
a <- c(1,2,5.3,6,-2,4); # numeric vector
b <- c("one","two","three"); # character vector
c <- c(TRUE,TRUE,TRUE,FALSE,TRUE,FALSE); #logical vector
v1 <- c(1, 5.5, 1e2);
v2 <- c(0.14, 0, -2);
v3 <- c(v1, v2);
v3[2];
## [1] 5.5
v3_sub <- v3[c(2,3)];
v1 %*% v2;
## [,1]
## [1,] -199.86
1:6;
## [1] 1 2 3 4 5 6
seq(from=1, to=12, by=4);
## [1] 1 5 9
ma <- matrix(1:6, nrow=3, ncol=2);
ma;
## [,1] [,2]
## [1,] 1 4
## [2,] 2 5
## [3,] 3 6
mb <- matrix(7:9, nrow=3, ncol=1);
mb;
## [,1]
## [1,] 7
## [2,] 8
## [3,] 9
rbind(ma, c(100, 200, 300));
## Warning in rbind(ma, c(100, 200, 300)): number of columns of result is not
## a multiple of vector length (arg 2)
## [,1] [,2]
## [1,] 1 4
## [2,] 2 5
## [3,] 3 6
## [4,] 100 200
m <- cbind(ma, mb);
m;
## [,1] [,2] [,3]
## [1,] 1 4 7
## [2,] 2 5 8
## [3,] 3 6 9
ncol(m);
## [1] 3
nrow(m);
## [1] 3
dim(m);
## [1] 3 3
t(m);
## [,1] [,2] [,3]
## [1,] 1 2 3
## [2,] 4 5 6
## [3,] 7 8 9
diag(m);
## [1] 1 5 9
#mymatrix <- matrix(vector, nrow=r, ncol=c, byrow=FALSE, dimnames=list(char_vector_rownames, char_vector_colnames));
y<-matrix(1:20, nrow=5,ncol=4);
cells <- c(1,26,24,68);
rnames <- c("R1", "R2");
cnames <- c("C1", "C2");
mymatrix <- matrix(cells, nrow=2, ncol=2, byrow=TRUE, dimnames=list(rnames, cnames));
#help(array);
d <- c(1,2,3,4);
e <- c("red", "white", "red", NA);
f <- c(TRUE,TRUE,TRUE,FALSE);
mydata <- data.frame(d,e,f);
names(mydata) <- c("ID","Color","Passed");
# variable gender with 20 "male" entries and 30 "female" entries
gender <- c(rep("male",20), rep("female", 30));
gender <- factor(gender);
# stores gender as 20 1s and 30 2s and associates 1=female, 2=male internally (alphabetically)
# R now treats gender as a nominal variable
# variable rating coded as "large", "medium", "small"
rating <- ordered(factor("large", "medium", "small"));
# recodes rating to 1,2,3 and associates 1=large, 2=medium, 3=small internally R now treats rating as ordinal
as.Date(NA);
## [1] NA
Sys.Date();
## [1] "2016-09-05"
date(); #datetime
## [1] "Mon Sep 05 13:32:21 2016"
#Format
#Convert
#help(as.Date)
#help(strftime)
#help(ISOdatetime)
# NA for all
# NULL only objects
#length(object); # number of elements or components
#str(object); # structure of an object
#class(object); # class or type of an object
#names(object); # names
#c(object,object,...); # combine objects into a vector
#cbind(object, object, ...); # combine objects as columns
#rbind(object, object, ...); # combine objects as rows
#object; # prints the object
#rm(object); # delete an object
#newobject <- edit(object); # edit copy and save as newobject
#fix(object); # edit in place
Stats for newbies